Patent GB-995790-A (GB)
Title: Photographic shutter control system
IPC: G03B7/00
Filed: 1963-01-25
Abstract: 995, 790. Photographic cameras. COMPURWERK G.m.b.H. Jan. 25, 1963 [March 14, 1962], No. 3160/63. Heading G2A. A photographic shutter is controlled by an electrical control system which controls the shutter by determining the period of delay between the operation of means to trip the shutter and the commencement of the shutter run-down movement for a set exposure period, the system including a plurality of R. C. circuits. A shutter opening ring 2 is retained by a catch 3 biased counter clockwise by a spring 4. Mounting pins 2c for pivoted blade members 6<SP>1</SP> to 6<SP>v</SP> are fixed to base plate 1. Pins 21a on a ring 21 actuate the members 6<SP>1</SP> to 6<SP>V</SP> to open position upon clockwise rotation of the ring 21. Pins 7 and 8 on the ring 21 co-operate with armatures 9 and 10. Permanent magnets 12 and 13 are secured to a shutter opening ring 2. A tension spring 20 is attached to the armature 10 and the ring 21 so urging the blade ring 21 clockwise, while a further spring 22 is attached between the armature 10 and opening ring 2. Stationary permanent magnets 14 and 15 have coils 14a, 15a and armature 16, 17 respectively. A cocking ring 23 has dogs 23a, 23b, and 23c arranged to engage armatures 10, 17, and 16 on clockwise rotation of ring 23. The ring 23 is urged counter-clockwise by a return spring (not shown), such that the dogs assume the position shown in Fig. 1 after cocking. A programme switch 36 having contact arms 36a, 36b, 36c, and 36d provides "V", "M", "X", "B" and "T" programmes, while a knob 34 adjusts a rheostat 34a to provide the required exposure time. Assuming programme X is required (to provide release of the shutter on operation of a trip button 35) the switch 36 is moved, such that arms 36a 36d move to the Fig. 1 position when pressure is applied to button 35 contact spring I engages contact a, so that a condenser 30 discharges through coil 12a of magnet 12; thereby releasing armature 9 and allowing spring 20 to turn blade ring 21 in the clockwise direction, thus opening blades 6<SP>1</SP> to 6v which when fully open complete a circuit for an electrance flash gun in known manner. Contacts 33a, 33b, and 33c are placed in the "r" position by a pin 7, thus coupling condenser 27 to battery 39 for charging to an extent dependent on the adjustment of rheostat 34a Condenser 27 is discharged when four layer diode 38 conducts current then flows through coil 13a setting up a field opposing coil 13a. Armature 10 is then released allowing spring 22 to return the ring 21 to shutter closed position Fig. 3 (not shown). During return of the ring 21 contacts 33a, 33b, and 33c are returned to "a" position. After re-cocking the shutter the trip operation can be repeated. Similarly, when the programme switch is in the "M" position condenser 28 is charged through contact 31a in the "a" position. When button 35 is pressed the contact spring I engages contact a to discharge condenser 28 through coil 15a. Condenser 30 is then charged providing a delay of 16 milliseconds, determined by the values of the resistance 26 and condenser 30, until diode 38 conducts. The "X" programme is then repeated to control the exposure period. In the "V" position of switch 36 the condenser 29 is charged through resistance 25 and is discharged through coil 14a, thereby causing contacts 32 to move to the "r" position. Condenser 28 is then charged through resistance giving a time delay of 8-10 seconds between the operation of trip button 35 and release of armature 9 to release the shutter. Condenser 30 is then charged as in programme "M" and the steps of that programme are then followed. With switch 36 in "B" position, the condenser 30 is charged through resistance 25 and then discharged through coil 12a when button 35 is depressed, thus releasing armature 9 for allowing rotation of ring 21 to open the shutter. The condenser 27 is simultaneously charged through resistance 37. When button 35 is released condenser 27 discharges through coil 13a, thereby releasing armature 10 and closing the shutter. With switch 36 in position "T" condenser 30 is charged through resistance 25 and then discharged upon depression of button 35 causing release of armature 9 and opening of the shutter. When button 35 is released condenser 27 is charged through resistance 25 and then discharges when button 37 is depressed through coil 13a. Armature 10 is released and the shutter is closed.